diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2018-07-20 11:53:15 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-07-21 22:42:41 -0700 |
| commit | 3d82475ad46c0b65f2618b5f2bbb4cadbb5ac5d8 (patch) | |
| tree | 7d0b385d1cae4803a33fb3ad6ac2e84561fa7559 | |
| parent | ff907a11a0d68a749ce1a321f4505c03bf72190c (diff) | |
| download | linux-3d82475ad46c0b65f2618b5f2bbb4cadbb5ac5d8.tar.gz | |
net: dsa: mv88e6xxx: fix races between lock and irq freeing
free_irq() waits until all handlers for this IRQ have completed. As the
relevant handler (mv88e6xxx_g1_irq_thread_fn()) takes the chip's reg_lock
it might never return if the thread calling free_irq() holds this lock.
For the same reason kthread_cancel_delayed_work_sync() in the polling case
must not hold this lock.
Also first free the irq (or stop the worker respectively) such that
mv88e6xxx_g1_irq_thread_work() isn't called any more before the irq
mappings are dropped in mv88e6xxx_g1_irq_free_common() to prevent the
worker thread to call handle_nested_irq(0) which results in a NULL-pointer
exception.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/dsa/mv88e6xxx/chip.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 437cd6eb4faa3..9ef07a06aceb6 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -343,6 +343,7 @@ static const struct irq_domain_ops mv88e6xxx_g1_irq_domain_ops = { .xlate = irq_domain_xlate_twocell, }; +/* To be called with reg_lock held */ static void mv88e6xxx_g1_irq_free_common(struct mv88e6xxx_chip *chip) { int irq, virq; @@ -362,9 +363,15 @@ static void mv88e6xxx_g1_irq_free_common(struct mv88e6xxx_chip *chip) static void mv88e6xxx_g1_irq_free(struct mv88e6xxx_chip *chip) { - mv88e6xxx_g1_irq_free_common(chip); - + /* + * free_irq must be called without reg_lock taken because the irq + * handler takes this lock, too. + */ free_irq(chip->irq, chip); + + mutex_lock(&chip->reg_lock); + mv88e6xxx_g1_irq_free_common(chip); + mutex_unlock(&chip->reg_lock); } static int mv88e6xxx_g1_irq_setup_common(struct mv88e6xxx_chip *chip) @@ -469,10 +476,12 @@ static int mv88e6xxx_irq_poll_setup(struct mv88e6xxx_chip *chip) static void mv88e6xxx_irq_poll_free(struct mv88e6xxx_chip *chip) { - mv88e6xxx_g1_irq_free_common(chip); - kthread_cancel_delayed_work_sync(&chip->irq_poll_work); kthread_destroy_worker(chip->kworker); + + mutex_lock(&chip->reg_lock); + mv88e6xxx_g1_irq_free_common(chip); + mutex_unlock(&chip->reg_lock); } int mv88e6xxx_wait(struct mv88e6xxx_chip *chip, int addr, int reg, u16 mask) @@ -4506,12 +4515,10 @@ out_g2_irq: if (chip->info->g2_irqs > 0) mv88e6xxx_g2_irq_free(chip); out_g1_irq: - mutex_lock(&chip->reg_lock); if (chip->irq > 0) mv88e6xxx_g1_irq_free(chip); else mv88e6xxx_irq_poll_free(chip); - mutex_unlock(&chip->reg_lock); out: if (pdata) dev_put(pdata->netdev); @@ -4539,12 +4546,10 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev) if (chip->info->g2_irqs > 0) mv88e6xxx_g2_irq_free(chip); - mutex_lock(&chip->reg_lock); if (chip->irq > 0) mv88e6xxx_g1_irq_free(chip); else mv88e6xxx_irq_poll_free(chip); - mutex_unlock(&chip->reg_lock); } static const struct of_device_id mv88e6xxx_of_match[] = { |